Methods and devices of the type indicated are frequently used to permit reconstruction of the events prior to an accident. The devices, also known as crash recorders (CR), are used as well to recognize accidents and to report accident information automatically to suitable central locations via radio communication network for the purpose of dealing with the accident more quickly.
German Published Patent Application No. 29 29 168 describes a method for acquiring, storing and evaluating driving data of vehicles. Using it, the intention is to reconstruct the speed conditions prior to an accident with great accuracy, without a sharp increase in outlay for storage. This is achieved by continually entering the acquired measured values into an erasable memory.
German Published Patent Application No. 41 32 981 describes a method for reconstructing the movement trajectory of a road vehicle. In this method, the movement of the vehicle prior to an accident event is described as a two-dimensional movement on the roadway surface. It starts from the assumption that during the braking process, the vehicle is moving in a straight line approximately in the direction of the vehicle longitudinal axis. In this case, longitudinal and transverse dynamic values are taken into account.
In the method described, at least two sensors for analog signals, as well as a measured-value acquisition device and a data memory are used. One of the analog signals carries information regarding the speed of the vehicle or its components in the vehicle longitudinal direction. With the assistance of a correlative measuring method, it and the movement of the vehicle are ascertained using a stationary evaluation unit, e.g. a digital computer, by resolution of a differential equation system. In this case, the method permits the detection of slippage-independent traveling speeds.
A disadvantage in the described method is that a new sensor system must be installed extra, and therefore the costs are very high.
In addition, an important disadvantage in known methods is that the vehicle movement is described in modulated fashion as a mass point, not completely as a three-dimensional object in its kinematics, namely translation and rotation.